Google revealed a glitch in what may be its second-most successful service, ranking only behind search.

The company confirmed Friday that some users of Gmail, its popular email service, had their email accounts wiped out, with messages and contact information being permanently deleted.

The glitch affected about 60 users, who “lost some or all of their email received prior to Dec. 18,” Google spokeswoman Courtney Hohne wrote in a prepared statement. “We have extensive safeguards in place to protect email stored with Gmail and we are confident that this is a small and isolated incident.”